Piston ring



Jan." 1o, 1933.

A. W. MORTN PISTON RING Filed June 3, 1932 Patented 10, 1933 UNITED STA-Tas PATENT OFFICE ALLEN W. MORTON, or BALTIMORE, MARYLANn AssIoNoR To TRE AMERICAN IIAMMERED :eIsTON RING COMPANY, or BALTIMORE, MARYLAND, `A CORPORATION 0F MARYLAND rIsTON RING Application led June 8,1932. Serial o. 615,218.

My invention relates to piston rings, and particularly to rings containing radial slots or openings employed to facilitate oil drainage as well as to control the circulation of the oil about the ring. j 1 This application constitutes an improvenrent on In (so-pending application, Ser. No. 530,963, fied Aprily 17, 1931, Patent No. 1,862,059, granted June 7, 1932. l

My improvement consists 'of a one-piece split ring containing series of spaced radial slots or openings, and series of aligning arcuate grooves in the outervface of the ring inr registry with certain of the-slots.

An object of my .invention is to y'produce aslotted oil ring containing seriesof radially disposed slots, all of said slots lying4 in a common plane located centrally of the side faces of the ring, and certain offwhich in each series are connected` in such manner as,y

to insure proper lubrication when such rings are installed in badly vworn cyllnders I Another object of my invention is Ito con# struct a ring Offthis character so as to avoid the formatlon of corners or pockets .which will arrest the flow kof Oil andA bring about the formation of carbon.

Still another object of the invention is to so form the parts of the ring as to facilitate rapid and practically unrestricted transfer of oil from the Outside to the inside of the ring, as well as to localize and control O11 circulation about the ring.

Other Objectswill appear from the folwith t e accompanying drawing, in which z- Fig. l is a view in elevation, with parts broken away, Oi one form ofeslotted ring i' embodying my invention;

Fi 2 is a section on line II--II of Fig. l, showing the relation of the ring to the cylinder wall after the ring becomes worn, the showing being somewhat exaggerated;

Fi 3 is a central horizontal section of the ring shown in li`ig. 1, the ring joint being o en 1 l.

pFig. 4 is a top plan view of a piston showing the position of the rings in a worn cylinder; and l Y Fig. 5 is a central horizontal section either side of said solid portions.

through a modied form of ring, in which the solid portions between adjacent slots are oi' rounded contour.' f

Referring first to Figs. 1 to 4 of the drawcated centrally of the side faces of the ring.

Adjacent slots are vconnected by cutting away the outer surface of the ring, as at 12.

' The bottoms of these cuts or grooves `12 are spaced rfrom the outer face of the ring, as

shownin Figs. 2 and 3. These cuts cooperate with the openings or slots which they con; nect, to form and define two independent coplanar series of interconnected openings or slots. of substantially 180 in extent, and diametricallyrelated.

, These series are separated at points 13 and' 14 byv solid portions of the ring which extend intact and imperforate from the inner to the outer face of thering or annulus, so that when the ring is in place in the cylinder and the ring joint is closed, oil circulation and drainage through the aperturing is provided throughout an extent of approximately 180 of the ring circumference on solid portions 13 and 14 of the ring are preferably displaced approximately 90 from a diametral plane passing through the ring joint, the plane coinciding substantially with the line designated A in Fig. 3.

These `The cuts 12 joining adjacent slots and coy operating with them are preferably of the same width as the slots, so as to provide ample oilcirculation grooves or ducts, and to make the sides of the slots continuous and luninterrupted between the 'inner and outer faces of the ring. These slots and grooves are of substantial' width, but form side lands 9 and 11 of sufficient section not to unduly` weaken the ring.

Iiind that material advantage results from 'forming the oil drainage slots and peripheral same planes with the sides of the grooves, as clearly sho-wn in Fig. 2 of the drawing. B such a construction, the path for the How ofy oil scraped off the cylinder by the oil scraping edges of the ring is unrestricted and the ring is properly ventilated, even in high speed, high compression engines of the most recent type.

This construction will be more evident from an examination of Fig. 2 of the drawing, wherein the line 15 designates the plane of one of the side walls of the slots 8, and this plane is also the plane. of the peripheral connecting groove or duct wall defined by the inner surface of the ring land 9. In similar manner, reference character 1.6 designates the continuous uninterrupted surface formed by the other wall of the slots and the inner face of ring land 1l.

It is almost universal practice to manufacture piston rings so that they have a plus circularity. This means that the ring diameter A (see Fig. 3) is greater than the ring diameter B when the ring with its joint closed is placed in a flexible band. This gives the ring greater tension on the diameter A than on the diameter B, and compensates for the weakening of the ring at the point where the joint is ont. By careful design, the amount of plus circularity can be so chosen as to give the ring satisfactory tension throughout its circumference.' In use, the face of the ring adjacent the joint and also diametrically across from the joint will wear away faster than the face of the ring at the ends of diameter B, because of the greater tension exerted along diameter A. This will result eventually in such wear that the diameter B becomes greater than the diameter A.

It is well known that engine cylinders become worn to elliptical form by the rocking of the piston or the side thrust of the piston because of the angularity of the connecting rod with respect to the axis of the piston.

l Consequently, in engines having badly worn cylinders the rings naturally assume such a position that their longer diameters coincide with the longer diameter of the worn cylinders. This means that in engines having badly worn cylinders the rings, after some degree of wear, generally take up a position with the diameter A approximately parallel to the axis of the wrist pin. By examining a great number of engines having worn cylinders, I have discovered that in the majority of cases the ring joints will be found to lie within an arc of approximately 450 one side or the other of the wrist pin axis.

This will be more clear from an examination of Fig. 4 of the drawing, wherein 18 designates the top of a piston having wrist pin bearings 19 containing a wrist pin 20. This piston is shown as containing the usual three piston rings, the joints of which are designated 2l, 22 and 223.

The axis of thewrist pin is designated 24. It will be found in the majority of cases that piston rings in worn cylinders will assume a position where their joints lie somewhere Within the arc-of angle 0, either one side or the other of the wrist pin axis. This means that the rings have been worn to minus circularity, i. e., that diameter B is greater than diameter A, and that the rings have shifted so that diameter B is approximately at right angles 'to this axis 24. It is well known that because ofthe rotation of an engine constantly in the same direction, oil tends to accumulate on one side of the piston or the cylinder, and in worn cylinders this accumulation occurs on. one side or the other of the wrist pin axis.

Accordingly, it is my purpose to provide at i least two series of peripherally connected slots in a ring and to separate the two series at point-s 13 and 14., so that when such rings are used in worn cylinders and the rings also become worn in, oil will be distributed throughout the area between the lines 25 and 26 at the ends of axis24 2nd will also be drained therefrom. The slots and short peripheral connecting grooves in each series provide arcuate outwardly open ducts through which the oil can flow without retardation and be distributed more or less evently over the face of the cylinder throughout its entire circumference without `any possibility of portions of the cylinder running dry.

In a piston ring containing a continuous groove, oil has a tendency to work around the ring always in the same direction, due to the particular shape of the cylinder caused by wear, i. e. either clockwise or counterclockwise. Consequently, one portion of the cyl inder may not receive suflicient oil since with a continuous groove with openings extending inwardly therefrom, the oil may pass to the rear of the ring before it is properly distributed. By forming two separate series of oil circulation and drainage aperturing, however, the tendency of the oil to circulate in one direction is lessened, and since the joints generally assume such positions that fliametral planes passing through them are substantially in line with the wrist pin axis, the. oil on the oily side of the piston or the cylinder is made to circulate in both directions, producing more uniform distribution.

Although the ring shown in Fig. 3 operates satisfactorily, I find that the retardation of oil can be lessened and the formation of pockets in which oil can collect substantially eliminated, by the structure shown in Fig. 5.

Referring now to this figure, the reference character 27 designates a one-piece split ring of the same character as that shown in Fig. 1. This ring contains radial slots 28, adjacent slots being connected by cuts or ducts 29, similar to those described with reference to Iig. 1. Likewise, these slots 28 are of the same width as the ducts 29, and cooperate with them to form two independent coplanar series of interconnected openings or slots, each series extending approximately 180 around the ring and separated by imperforate portions of the ring or annulus 31 and 32, which form solid walls that extend across the face of the annulus and are intact from its inner face entirely to its. peripheral face, in a manner similar to solid portions 13 and 14 of the ring shown in Fig. 1..

The ring shown in Fig. 5, in which the outer faces 34: of the portions 33 forming the end Walls of adjacent slots are of smooth rounded contour, provides a construction whereby any possible restriction in the connecting passages of adjacent slots is reduced to a minimum, and eddying of the oil is substantially wholly eliminated.

By reference to Fig. 5, it will be noted that the outer rounded faces 34 merge into the diverging portions 35 and 36 without abrupt transltion. Consequently, when oil circulates around the ring through the ducts 29 from one slot to another, it encounters no sharp edges or corners to impede its movement, hence all tendencies to eddy or burble are substantially eliminated. ln this figure, l have shown the ring as provided with solid imperforate portions separating each series of slots, but it will be obvious that the advantages of the rounded connecting portions between adjacent slots will still be present if the solid portions are omitted. Accordingly, l wish it to be understood that rings embodying the rounded surfaces, as described, will function to prevent eddying of the oil regardless of the presence or absence of the solid portions. l, therefore, desire to claim generically rings having 'this rounded contour, and in which these solid portions may or may not be present.

The type of ring shown in Fig. 5 not only results in improved operation, but it can be more easily manufactured. According to the principles of hydraulics, it vcan be demonstrated that the structures as above described materially improve the circulation of the oil, thereby reducing tendencies to carbon formation resulting from a too restricted'or retarded flow of oil.

lt will be clear from the above description that l have designed a ring which will not only aord sufficient cylinder contacting area without undue weakening of the ring, but will facilitate uniform, rapid and unrestricted oil circulation and drainage in an improved manner which has not been known heretofore.

Although have shown and described only two forms of piston rings embodying my invention, it will be obvious that changes may be made in the details, within the scope of the claims, without departing from the spirit and scope of my invention.

,What is claimed is:

l. A. piston ring comprising a one-piece split annulus having centrally located intermediate its sides a single row composed of two end-to-end series of elongated slots having parallel sides and outwardly flaring end walls and severally aperturing the annulus from its inner face outwardly toward its periphery, theseries being separated from each other at points that are respectively about 90 from the split in the annulus, by solid portions of the annulus that are intact and im erforate from their inner faces entirely to t eir peripheral faces, and the slots constituting each series having their outermost mutually adjacent ends communicably connected by short peripheral grooves; whereby each series of slots constitutes within itself a substantially continuous oil-circulation aperturing of the annulus, while the series are severally separated from and out of communication with each other and thereby severally localize the oil-circulation aperturing that they respectively provide.

2. A split piston ring containin a plurality of coplanar radial slots openlng on the inner surface of the ring and separated by solid portions of the ring, certain of said radial slots adjacent the split and diametrically opposite theretofbeing communicably connected by short peripheral grooves of the same width as the slots and aligned therewith, said grooves being interrupted at two diarnetral points displaced substantially 90 from the ring joint, and said ooves forming in the outer face of the solld portions of the ring outwardly open oil-circulation ducts merging into the ends of said radial slots.

3. A piston ring comprising a split annulus having a plurality of coplanar radial openings therethrough and a series of coplanar grooves in its cylinder contacting face connecting said openings, the openings having side walls parallel to the plane faces of the ring and end walls of smooth outwardly curved formation merging into the adjacent grooves.

4. A ring as set forth in claim 3, wherein the opening-connectin grooves are omitted at diametral points t ereby producing cylinder contacting faces coextensive of the width of the ring.

ln testimony whereof l have signed my i name to this specification.

ALLEN W. MG'RTON. 

